Climate change disrupting biodiversity

Plants and animals are shifting their ranges and life cycles in response to climate change, creating clashes between unfamiliar creatures or mismatches between animals and their food sources, according to a new national biodiversity report.

The analysis could expand the scope of conservation efforts, which for 40 years has focused predominantly on habitat changes, local wildlife experts said.

“Climate change has this incredibly large footprint of effects,” said Megan Owen, conservation program manager at the San Diego Zoo Institute for Conservation Research. “Now we’re seeing this synergy of habitat loss, habitat degradation and climate change.”

More than 60 federal, academic and other scientists contributed to the national report, led by the U.S. Geological Survey and several universities and environmental groups. Released last month, it will be used as scientific input for the 2013 National Climate Assessment, a federally required analysis of research.

The last climate assessment, in 2009, drew controversy when the libertarian Cato Institute published a so-called addendum, challenging it as incomplete and out-of-date with peer-review studies. Cato, among others, contends that the effects of climate change are more modest than stated in the assessment.

This year’s report, which analyzed several hundred individual scientific studies, said there is evidence that species are relocating to new ranges, and that those which can’t move are declining, or even disappearing.

“Biodiversity and ecosystems are already more stressed than at any comparable period of human history,” the report stated. “Climate change almost always exacerbates the problems caused by other environmental stressors.”

The report cautioned, however, that predictions about biodiversity changes in future decades are uncertain because of the variability of climate projections. It also noted gaps in scientists’ knowledge of biological and ecological responses to climate change.

California has some of the highest biodiversity in the country, and the greatest number of vulnerable species of any state except Hawaii, according to the report.

Species are shifting to northern latitudes and higher altitudes faster than scientists had previously observed, the report found.

Land animals are climbing in elevation at rates two to three times greater than initial estimates, migrating to cooler, higher ground as their original habitat heats up, the report calculated.

Those findings dovetail with local research showing that high-altitude species in Southern California mountains are changing their range.

A San Diego Natural History Museum team that is retracing the historic Grinnell transect of the San Jacinto Mountains, found that several conifers have shifted elevations, while some small mammals and birds have vanished entirely.

The flying squirrel, lodgepole chipmunk and sharp-shinned hawk, observed by zoologist Joseph Grinnell in 1908, couldn’t be seen in the San Jacintos this year, said Phil Unitt, curator of birds and mammals for the museum. And certain trees have retreated up the mountain.

“We see the pinyon and white fir and the California juniper very conspicuously dying off at the lower limits of their elevation ranges,” Unitt said.

Meanwhile pests such as bark beetles, which benefit from warmer winters, are spreading in Western forests.

“There’s a lot of surprises in the way that biodiversity is responding to climate change impacts,” said Michelle Staudinger, lead author of the report, and a scientist with the University of Missouri and the U.S. Geological Survey. “Not all plants and animals are responding the same way.”